During the period 1991 to late 1993 there was a large increase in harm reduction programmes in Dublin. These services include including methadone treatment, education regarding safer injecting and syringe exchange. This study investigated whether injecting drug users with short injecting histories would have a lower prevalence of hepatitis C virus (HCV) than those who started injecting during the period after an expansion in harm reduction programs. 343 injecting drug users with an injection history less than 25 months tested for the anti-HCV between 1993 and 1996 were included in the study. Results show that the prevalence of anti-HCV was 52.1%. Those who started injecting in the period after January 1994 and those with injecting histories less that 13 month demonstrated significantly reduced risks of infection. While the authors accept that the detection of a declining prevalence of HCV infection after an expansion of services does not conclusively prove causality, it is still an encouraging finding.